Although I am sure that no one ever sets out to become a drug addict, the fact remains that they did make the conscious decision to take drugs in the first place. At what point the addiction takes over from the conscious decision is anyone's guess and it is probably unique to each individual.

Interestingly, a study at the University of North Carolina has found that addicts may be naturally more impulsive than other people and therefore less capable of making wise long-term decisions.

During the study, recovering alcoholics were given a variety of financial decision tasks to perform which broadly meant them choosing between "less money now" or "more money later". The alcoholics chose the "now" reward almost three times as often as the "later" option.

Brain scans of the subjects revealed that compared to the norm for non-alcoholics, they had lower levels of activity in the orbitofrontal cortex (OFC), the part of the brain that helps us make wise long-term decisions.

It is known that drug addiction is a highly heritable disorder. Eric J Nestler of the University of Texas Southwestern Medical Centre discovered in 2000 that 40-60% of the risk of alcohol, cocaine or opiate addiction appears to be genetic. But little is known why this is the case or what the possible cures might be. It is therefore interesting that this study found a genetic link with the brain chemical dopamine. It may therefore be that in the fullness of time a medical cure for some forms of addiction may involve artificially increasing dopamine levels.